This invention relates to a roller for guiding and/or conveying a web of material, like in a textile processing machine, said roller comprising a jacket of stainless steel with a filling of foam plastic and two end covers each provided with a trunnion. Such rollers are used in large quantities in machines for washing, chemically treating, drying etc textile material. Their usual dimensions are 150 mm in diameter and 2000 mm in length.
Owing to the aggresive medium by means of which the aimed treatment is often carried out, the roller has a jacket of stainless steel. Since this material is rather expensive, the jacket is made as thin as possible while a filling of foam plastic is used to impart sufficient strength and bending resistance to the roller. Thus the roller gets light in weight and has only a small mass. The roller should meet high requirements as to its precise cylindrical shape, since otherwise disturbing forces or influences would arise in the conveyed textile web with a risk of creases being formed or the like. The rollers in a textile processing machine are further subjected to a rather considerable load, owing to the pull exerted on them by the web of material to be guided.
In order to keep the rollers in good shape it is therefore of great importance that apart from sufficient strength and bending resistance, the two supporting trunnions at both ends of each roller are rigidly and efficiently secured. The foam plastic within each roller offers only little support in this respect, particularly in case of varying loads due to the rotation of the rollers. With respect to the above, various structural solutions have been proposed to anchor the supporting trunnions not only exactly centrally but also rigidly in the hart of the roller. These solutions have so far appeared to be inefficient or to use much labour, which prevented an extensive use of these rollers which are in great demand. Not only the strength but also the cost price of the roller are of importance.